Early watercraft propulsion was often provided by paddle wheel systems including a rotating wheel partially submerged in water to provide forward propulsion. Such paddle wheel systems were largely replaced by underwater propellers, which were found to be more efficient when adequate water depth permitted their use.
Continuous track propulsion systems for amphibious vehicles and snowmobiles are known. These continuous track propulsion systems operate on the same general principal as a paddle wheel when utilized for waterborne propulsion, but offering the advantage of keeping a larger portion of the drive train perpendicular to water and therefore offering better efficiency than conventional paddle wheel designs. It is also known that a modern snowmobile can operate across the surface of water when dynamic lift from its track drive system keeps the nose of the snowmobile lifted and the skis ‘skim’ the surface of the water. However, when a conventional snowmobile slows down or stops on the surface of water, it will sink because of the lack of positive buoyancy and the lessening of the dynamic lift provided by the track drive system.
The present invention is configured to take advantage of a continuous track propulsion system, while incorporating it into an outboard motor, and coupling it with existing boats that can accept a standard transom-mounted motor and provide flotation with the advantages of a standard designed boat.
More particularly, the continuous track outboard motor (CTOM) for watercraft propulsion of the present disclosure is configured to be a modular, transom-mounted boat motor that better enables boat operation in shallow and/or obstructed water, where mud, sand, rocks, vegetation, logs, snags, frozen and semi-frozen surfaces, and other obstacles may be impediments to a standard propeller-driven outboard motor. Even specialty surface-drive “mud motors” typically cannot traverse ice or beach scenarios, where the illustrative continuous track outboard motor of the present disclosure can operate. The watercraft propulsion system of the present disclosure is intended to better enable shallow water operations for military, search and rescue, and recreational (e.g., hunting and fishing) small boat operators, by providing a reliable and simple drive mechanism that offers multiple advantages over alternatives such as air boats, air cushion vehicles (hovercraft), mud motors, or other amphibious vehicle propulsion systems.
According to an illustrative embodiment of the present disclosure, a watercraft propulsion system includes an outboard motor, a suspension frame supported below the motor, a drive wheel supported by the suspension frame and operably coupled to the motor, a first driven wheel supported by the suspension frame in spaced relation to the drive wheel, and a second driven wheel supported by the suspension frame in spaced relation to the drive wheel and the first driven wheel. A continuous track is supported by the drive wheel, the first driven wheel and the second driven wheel, the continuous track including an upper run engaging the first driven wheel, the second driven wheel and the drive wheel, and a lower run engaging the first driven wheel and the second driven wheel, the lower run extending below the upper run and including a downwardly facing water engagement surface. A transom mount is configured to couple the motor to the transom of a boat, the transom mount including a trim control for vertical adjustment of the suspension frame relative to the transom, and a tilt control for pivoting adjustment of the suspension frame relative to the transom.
According to another illustrative embodiment of the present disclosure, a watercraft propulsion system includes an outboard motor, a suspension frame supported by the motor, a drive wheel operably coupled to the motor, a first driven wheel supported by a suspension frame in spaced relation to the drive wheel, and a second driven wheel supported by the suspension frame in spaced relation to the drive wheel and the first driven wheel, a track path defined between the drive wheel, the first driven wheel and the second driven wheel. A continuous track is supported by the drive wheel, the first driven wheel and the second driven wheel, the continuous track including a downwardly facing water engagement surface. The suspension frame includes a base member and an upright member coupled to the base member. A base actuator is coupled to the base member for adjusting the length of the base member, and an upright actuator is coupled to the upright member for adjusting the length of the upright member. The distance between the first driven wheel and the second driven wheel may be adjusted to vary the water engagement surface. A controller is operably coupled to the base actuator and the upright actuator for maintaining a constant length of the track path as the length of the base member and the length of the upright member of the suspension frame are adjusted.
According a further illustrative embodiment of the present disclosure, a method of propelling a watercraft includes the steps of providing a boat including a transom, providing an adjustable suspension frame coupled to the transom of the boat, and rotating a continuous track on the suspension frame, wherein the continuous track includes an upper run engaging a first driven wheel, a second driven wheel, and a drive wheel, and a lower run engaging the first driven wheel and the second driven wheel, the lower run extending below the upper run and including a downwardly facing water engagement surface. The method further includes the steps of detecting the speed of the continuous track, and varying the downwardly facing water engagement surface of the continuous track contacting the water based upon the detected speed.
Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrative embodiment exemplifying the best mode of carrying out the invention as presently perceived.